b591270628
Certain platforms have a poorly performing SPI prefetcher so even if accessing MMIO BIOS once the fetch time can be impacted. Payload loading is one example where it can be impacted. Therefore, add the ability for a platform to reconfigure the currently running CPU's variable MTRR settings for the duration of coreboot's execution. The function mtrr_use_temp_range() is added which uses the previous MTRR solution as a basis along with a new range and type to use. A new solution is calculated with the updated settings and the original solution is put back prior to exiting coreboot into the OS or payload. Using this patch on apollolake reduced depthcharge payload loading by 75 ms. BUG=chrome-os-partner:56656,chrome-os-partner:59682 BRANCH=None TEST=None Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/17371 Tested-by: build bot (Jenkins) Reviewed-by: Furquan Shaikh <furquan@google.com> Reviewed-by: Andrey Petrov <andrey.petrov@intel.com> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Change-Id: If87ee6f88e0ab0a463eafa35f89a5f7a7ad0fb85 Reviewed-on: https://chromium-review.googlesource.com/411436 Commit-Ready: Furquan Shaikh <furquan@chromium.org> Tested-by: Furquan Shaikh <furquan@chromium.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org> |
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| cpu.h | ||